Conventionally, there have been used drive power transmission devices that transmit drive power of an input shaft to an output shaft while changing angular velocity or torque. For example, JP 2012-251619 A discloses a continuously variable transmission device serving as a drive power transmission device for a vehicle.
In the above-noted continuously variable transmission device, the output shaft is arranged parallel to the input shaft. The input shaft is provided with six eccentric mechanisms that rotate eccentrically in accordance with rotation of the input shaft. The eccentric mechanisms are arranged around the input shaft with the respective centers of the eccentric mechanisms being phase-shifted from each other by 60 degrees. The continuously variable transmission device comprises swing links that swing and rotate in a pushing direction and a returning direction during rotation of the eccentric mechanisms. The continuously variable transmission device further comprises clutches for engaging the swing links and the output shaft with each other.
The continuously variable transmission device intermittently transmits drive power of the input shaft to the output shaft. More specifically, when an eccentric mechanism rotates in accordance with rotation of the input shaft, a corresponding swing link is caused to swing and rotate in the pushing direction. During that time, a corresponding clutch causes the swing link and the output shaft to be engaged with each other, thereby causing the output shaft to rotate. When the swing link swings and rotates in the returning direction, the engagement by the clutch is released. In this way, the respective swing links are sequentially engaged with the output shaft, and, at each instance of the engagement, the output shaft is caused to rotate by 60 degrees.